Donald Trump’s bid to silence an author who claims the developer is worth far less than the billions he claims was dealt a major blow after a New Jersey judge tossed out the case yesterday.

“The Apprentice” star had sued author Timothy O’Brien for libel after his 2005 book “TrumpNation,” citing anonymous sources, claimed Trump was worth between $150 million and $250 million — not the $5 billion to $6 billion Trump himself asserts.

Judge Michelle Fox in a state court in Camden, NJ, made a verbal ruling tossing out the case.

The two-year-old case put a spotlight on a subject that has been heavily debated over the years. While Trump as recently as yesterday insisted that he is worth as much as $6 billion, analyses conducted over the years suggest otherwise.

In addition to O’Brien’s valuation, The Wall Street Journal earlier this year reported that an appraisal done by Deutsche Bank in 2005 pegged Trump’s worth at $788 million — a figure the Donald balked at because he said it didn’t take all of his assets into account.

Yet even Trump himself has acknowledged his net worth is a moving target.

During a deposition for the libel case, he conceded that his net worth “fluctuates” based on a variety of factors.

“My net worth fluctuates, and it goes up and down with markets and with attitudes and with feelings — even my own feelings,” Trump said in a 2007 deposition, in which he also said that the valuation of his net worth of over $4 billion “is a very conservative number.”

Yesterday, he told The Post he’s worth between $5 billion and $6 billion.

“We’ve proven our case,” he insisted. “When you’re worth over $5 billion or $6 billion and you’ve proven that, you still have to prove malice. The libel laws are very bad.”

O’Brien, whose day job is the Sunday business editor of The New York Times, said in a statement, “I’m deeply grateful that the court’s decision has vindicated the reporting in ‘TrumpNation.’ ”